fix(soul): installers seed the real default persona, upgrade legacy empty templates (#52246)

The desktop bootstrap (and curl/PowerShell/docker installs) seeded
~/.hermes/SOUL.md with a comment-only scaffold that contained no persona
text. That shadowed the runtime default (_ensure_default_soul_md ->
DEFAULT_SOUL_MD), since seeding is guarded by 'if SOUL.md doesn't exist'.
Result: every fresh installer install got the empty template instead of
the documented Hermes persona; desktop just made it visible in onboarding.

- install.sh / install.ps1 / docker/SOUL.md now write DEFAULT_SOUL_MD.
- _ensure_default_soul_md() upgrades a SOUL.md still matching the known
  legacy scaffold in place; customized files (any deviation, incl. a
  persona appended below the comment) are never touched.
- Detection normalizes CRLF/BOM so Windows-installer drift still matches.

scripts/install.ps1

@@ -2025,22 +2025,11 @@ function Copy-ConfigTemplates {
     # PowerShell version.
     $soulPath = "$HermesHome\SOUL.md"
     if (-not (Test-Path $soulPath)) {
+        # MUST match DEFAULT_SOUL_MD in hermes_cli/default_soul.py. The runtime
+        # upgrades the old comment-only scaffold to this text on next run, so
+        # drift is self-healing, but keep them in sync to avoid first-run churn.
         $soulContent = @"
-# Hermes Agent Persona
-
-<!--
-This file defines the agent's personality and tone.
-The agent will embody whatever you write here.
-Edit this to customize how Hermes communicates with you.
-
-Examples:
-  - "You are a warm, playful assistant who uses kaomoji occasionally."
-  - "You are a concise technical expert. No fluff, just facts."
-  - "You speak like a friendly coworker who happens to know everything."
-
-This file is loaded fresh each message -- no restart needed.
-Delete the contents (or this file) to use the default personality.
--->
+You are Hermes Agent, an intelligent AI assistant created by Nous Research. You are helpful, knowledgeable, and direct. You assist users with a wide range of tasks including answering questions, writing and editing code, analyzing information, creative work, and executing actions via your tools. You communicate clearly, admit uncertainty when appropriate, and prioritize being genuinely useful over being verbose unless otherwise directed below. Be targeted and efficient in your exploration and investigations.
 "@
         $utf8NoBom = New-Object System.Text.UTF8Encoding($false)
         [System.IO.File]::WriteAllText($soulPath, $soulContent, $utf8NoBom)

scripts/install.sh

@@ -1727,24 +1727,14 @@ copy_config_templates() {
         log_info "~/.hermes/config.yaml already exists, keeping it"
     fi
 
-    # Create SOUL.md if it doesn't exist (global persona file)
+    # Create SOUL.md if it doesn't exist (global persona file).
+    # This MUST match DEFAULT_SOUL_MD in hermes_cli/default_soul.py — the
+    # runtime (_ensure_default_soul_md) treats the old comment-only scaffold as
+    # "never customized" and upgrades it to this text on next run, so any drift
+    # here is self-healing, but keep them in sync to avoid a churn on first run.
     if [ ! -f "$HERMES_HOME/SOUL.md" ]; then
         cat > "$HERMES_HOME/SOUL.md" << 'SOUL_EOF'
-# Hermes Agent Persona
-
-<!--
-This file defines the agent's personality and tone.
-The agent will embody whatever you write here.
-Edit this to customize how Hermes communicates with you.
-
-Examples:
-  - "You are a warm, playful assistant who uses kaomoji occasionally."
-  - "You are a concise technical expert. No fluff, just facts."
-  - "You speak like a friendly coworker who happens to know everything."
-
-This file is loaded fresh each message -- no restart needed.
-Delete the contents (or this file) to use the default personality.
--->
+You are Hermes Agent, an intelligent AI assistant created by Nous Research. You are helpful, knowledgeable, and direct. You assist users with a wide range of tasks including answering questions, writing and editing code, analyzing information, creative work, and executing actions via your tools. You communicate clearly, admit uncertainty when appropriate, and prioritize being genuinely useful over being verbose unless otherwise directed below. Be targeted and efficient in your exploration and investigations.
 SOUL_EOF
         log_success "Created ~/.hermes/SOUL.md (edit to customize personality)"
     fi