feat(skills+terminal): make bundled skill scripts runnable out of the box (#13384)

* feat(skills): inject absolute skill dir and expand ${HERMES_SKILL_DIR} templates

When a skill loads, the activation message now exposes the absolute
skill directory and substitutes ${HERMES_SKILL_DIR} /
${HERMES_SESSION_ID} tokens in the SKILL.md body, so skills with
bundled scripts can instruct the agent to run them by absolute path
without an extra skill_view round-trip.

Also adds opt-in inline-shell expansion: !`cmd` snippets in SKILL.md
are pre-executed (with the skill directory as CWD) and their stdout is
inlined into the message before the agent reads it. Off by default —
enable via skills.inline_shell in config.yaml — because any snippet
runs on the host without approval.

Changes:
- agent/skill_commands.py: template substitution, inline-shell
  expansion, absolute skill-dir header, supporting-files list now
  shows both relative and absolute forms.
- hermes_cli/config.py: new skills.template_vars,
  skills.inline_shell, skills.inline_shell_timeout knobs.
- tests/agent/test_skill_commands.py: coverage for header, both
  template tokens (present and missing session id), template_vars
  disable, inline-shell default-off, enabled, CWD, and timeout.
- website/docs/developer-guide/creating-skills.md: documents the
  template tokens, the absolute-path header, and the opt-in inline
  shell with its security caveat.

Validation: tests/agent/ 1591 passed (includes 9 new tests).
E2E: loaded a real skill in an isolated HERMES_HOME; confirmed
${HERMES_SKILL_DIR} resolves to the absolute path, ${HERMES_SESSION_ID}
resolves to the passed task_id, !`date` runs when opt-in is set, and
stays literal when it isn't.

* feat(terminal): source ~/.bashrc (and user-listed init files) into session snapshot

bash login shells don't source ~/.bashrc, so tools that install themselves
there — nvm, asdf, pyenv, cargo, custom PATH exports — stay invisible to
the environment snapshot Hermes builds once per session.  Under systemd
or any context with a minimal parent env, that surfaces as
'node: command not found' in the terminal tool even though the binary
is reachable from every interactive shell on the machine.

Changes:
- tools/environments/local.py: before the login-shell snapshot bootstrap
  runs, prepend guarded 'source <file>' lines for each resolved init
  file.  Missing files are skipped, each source is wrapped with a
  '[ -r ... ] && . ... || true' guard so a broken rc can't abort the
  bootstrap.
- hermes_cli/config.py: new terminal.shell_init_files (explicit list,
  supports ~ and ${VAR}) and terminal.auto_source_bashrc (default on)
  knobs.  When shell_init_files is set it takes precedence; when it's
  empty and auto_source_bashrc is on, ~/.bashrc gets auto-sourced.
- tests/tools/test_local_shell_init.py: 10 tests covering the resolver
  (auto-bashrc, missing file, explicit override, ~/${VAR} expansion,
  opt-out) and the prelude builder (quoting, guarded sourcing), plus
  a real-LocalEnvironment snapshot test that confirms exports in the
  init file land in subsequent commands' environment.
- website/docs/reference/faq.md: documents the fix in Troubleshooting,
  including the zsh-user pattern of sourcing ~/.zshrc or nvm.sh
  directly via shell_init_files.

Validation: 10/10 new tests pass; tests/tools/test_local_*.py 40/40
pass; tests/agent/ 1591/1591 pass; tests/hermes_cli/test_config.py
50/50 pass.  E2E in an isolated HERMES_HOME: confirmed that a fake
~/.bashrc setting a marker var and PATH addition shows up in a real
LocalEnvironment().execute() call, that auto_source_bashrc=false
suppresses it, that an explicit shell_init_files entry wins over the
auto default, and that a missing bashrc is silently skipped.

tests/tools/test_local_shell_init.py

@@ -0,0 +1,162 @@
+"""Tests for terminal.shell_init_files / terminal.auto_source_bashrc.
+
+A bash ``-l -c`` invocation does NOT source ``~/.bashrc``, so tools that
+register themselves there (nvm, asdf, pyenv) stay invisible to the
+environment snapshot built by ``LocalEnvironment.init_session``.  These
+tests verify the config-driven prelude that fixes that.
+"""
+
+import os
+from unittest.mock import patch
+
+import pytest
+
+from tools.environments.local import (
+    LocalEnvironment,
+    _prepend_shell_init,
+    _read_terminal_shell_init_config,
+    _resolve_shell_init_files,
+)
+
+
+class TestResolveShellInitFiles:
+    def test_auto_sources_bashrc_when_present(self, tmp_path, monkeypatch):
+        bashrc = tmp_path / ".bashrc"
+        bashrc.write_text('export MARKER=seen\n')
+        monkeypatch.setenv("HOME", str(tmp_path))
+
+        # Default config: auto_source_bashrc on, no explicit list.
+        with patch(
+            "tools.environments.local._read_terminal_shell_init_config",
+            return_value=([], True),
+        ):
+            resolved = _resolve_shell_init_files()
+
+        assert resolved == [str(bashrc)]
+
+    def test_skips_bashrc_when_missing(self, tmp_path, monkeypatch):
+        # No bashrc written.
+        monkeypatch.setenv("HOME", str(tmp_path))
+
+        with patch(
+            "tools.environments.local._read_terminal_shell_init_config",
+            return_value=([], True),
+        ):
+            resolved = _resolve_shell_init_files()
+
+        assert resolved == []
+
+    def test_auto_source_bashrc_off_suppresses_default(self, tmp_path, monkeypatch):
+        bashrc = tmp_path / ".bashrc"
+        bashrc.write_text('export MARKER=seen\n')
+        monkeypatch.setenv("HOME", str(tmp_path))
+
+        with patch(
+            "tools.environments.local._read_terminal_shell_init_config",
+            return_value=([], False),
+        ):
+            resolved = _resolve_shell_init_files()
+
+        assert resolved == []
+
+    def test_explicit_list_wins_over_auto(self, tmp_path, monkeypatch):
+        bashrc = tmp_path / ".bashrc"
+        bashrc.write_text('export FROM_BASHRC=1\n')
+        custom = tmp_path / "custom.sh"
+        custom.write_text('export FROM_CUSTOM=1\n')
+        monkeypatch.setenv("HOME", str(tmp_path))
+
+        # auto_source_bashrc stays True but the explicit list takes precedence.
+        with patch(
+            "tools.environments.local._read_terminal_shell_init_config",
+            return_value=([str(custom)], True),
+        ):
+            resolved = _resolve_shell_init_files()
+
+        assert resolved == [str(custom)]
+        assert str(bashrc) not in resolved
+
+    def test_expands_home_and_env_vars(self, tmp_path, monkeypatch):
+        target = tmp_path / "rc" / "custom.sh"
+        target.parent.mkdir()
+        target.write_text('export A=1\n')
+        monkeypatch.setenv("HOME", str(tmp_path))
+        monkeypatch.setenv("CUSTOM_RC_DIR", str(tmp_path / "rc"))
+
+        with patch(
+            "tools.environments.local._read_terminal_shell_init_config",
+            return_value=(["~/rc/custom.sh"], False),
+        ):
+            resolved_home = _resolve_shell_init_files()
+
+        with patch(
+            "tools.environments.local._read_terminal_shell_init_config",
+            return_value=(["${CUSTOM_RC_DIR}/custom.sh"], False),
+        ):
+            resolved_var = _resolve_shell_init_files()
+
+        assert resolved_home == [str(target)]
+        assert resolved_var == [str(target)]
+
+    def test_missing_explicit_files_are_skipped_silently(self, tmp_path, monkeypatch):
+        monkeypatch.setenv("HOME", str(tmp_path))
+        with patch(
+            "tools.environments.local._read_terminal_shell_init_config",
+            return_value=([str(tmp_path / "does-not-exist.sh")], False),
+        ):
+            resolved = _resolve_shell_init_files()
+
+        assert resolved == []
+
+
+class TestPrependShellInit:
+    def test_empty_list_returns_command_unchanged(self):
+        assert _prepend_shell_init("echo hi", []) == "echo hi"
+
+    def test_prepends_guarded_source_lines(self):
+        wrapped = _prepend_shell_init("echo hi", ["/tmp/a.sh", "/tmp/b.sh"])
+        assert "echo hi" in wrapped
+        # Each file is sourced through a guarded [ -r … ] && . '…' || true
+        # pattern so a missing/broken rc can't abort the bootstrap.
+        assert "/tmp/a.sh" in wrapped
+        assert "/tmp/b.sh" in wrapped
+        assert "|| true" in wrapped
+        assert "set +e" in wrapped
+
+    def test_escapes_single_quotes(self):
+        wrapped = _prepend_shell_init("echo hi", ["/tmp/o'malley.sh"])
+        # The path must survive as the shell receives it; embedded single
+        # quote is escaped as '\'' rather than breaking the outer quoting.
+        assert "o'\\''malley" in wrapped
+
+
+@pytest.mark.skipif(
+    os.environ.get("CI") == "true" and not os.path.isfile("/bin/bash"),
+    reason="Requires bash; CI sandbox may strip it.",
+)
+class TestSnapshotEndToEnd:
+    """Spin up a real LocalEnvironment and confirm the snapshot sources
+    extra init files."""
+
+    def test_snapshot_picks_up_init_file_exports(self, tmp_path, monkeypatch):
+        init_file = tmp_path / "custom-init.sh"
+        init_file.write_text(
+            'export HERMES_SHELL_INIT_PROBE="probe-ok"\n'
+            'export PATH="/opt/shell-init-probe/bin:$PATH"\n'
+        )
+
+        with patch(
+            "tools.environments.local._read_terminal_shell_init_config",
+            return_value=([str(init_file)], False),
+        ):
+            env = LocalEnvironment(cwd=str(tmp_path), timeout=15)
+            try:
+                result = env.execute(
+                    'echo "PROBE=$HERMES_SHELL_INIT_PROBE"; echo "PATH=$PATH"'
+                )
+            finally:
+                env.cleanup()
+
+        output = result.get("output", "")
+        assert "PROBE=probe-ok" in output
+        assert "/opt/shell-init-probe/bin" in output