feat(commands): /compact alias + --preview/--dry-run flags for /compress (#3243 salvage)

Salvaged from PR #3243 by @Mibayy, reimplemented against current main
(the original diff targeted a removed gateway/run.py handler).

- /compact is now a first-class alias of /compress (CLI, gateway,
  Telegram/Slack/Discord command lists, autocomplete) — also fixes the
  dangling '/compact' references in gateway error messages
  (gateway/run.py context-exhausted banners).
- --preview / --dry-run: report what WOULD be compressed (message
  counts, token estimate, 'here [N]' boundary) without touching the
  transcript. Flags coexist with the existing 'here [N]' / focus-topic
  args on both the CLI and gateway surfaces via shared pure helpers in
  hermes_cli/partial_compress.py.
- --aggressive (LLM-free hard truncation) is intentionally NOT
  implemented: it would need its own transcript-persistence branch
  outside the guarded _compress_context rotation machinery (#44794
  data-loss class). The flag is recognized and returns an explanatory
  message pointing at '/compress here [N]' and /undo instead of being
  mis-parsed as a focus topic.
- locales: gateway.compress.aggressive_unsupported added to all 16
  catalogs (parity test enforced).
- release.py: AUTHOR_MAP entry for contributor credit.

scripts/release.py

@@ -45,6 +45,7 @@ ACP_REGISTRY_MANIFEST = REPO_ROOT / "acp_registry" / "agent.json"
 
 # Auto-extracted from noreply emails + manual overrides
 AUTHOR_MAP = {
+    "louis@letsfive.io": "Mibayy",  # PR #3243 salvage (/compact alias + preview/aggressive flags for /compress)
     "ai-lab@foxmail.com": "CrazyBoyM",  # PR #55828 salvage (image_gen openai-codex: wire image-to-image / reference-image editing via Codex Responses input_image parts; magic-byte + read-guard + 25MB-cap + clamp-to-16 hardening)
     "r0gersm1th@users.noreply.github.com": "r0gersm1th",  # PR #3219 salvage (whatsapp bridge: resolve LID sender IDs to phone numbers in the message payload so phone-based allowlists match; commit authored by collaborator r0gersm1th, PR by @ajmeese7)
     "louis@letsfive.io": "Mibayy",  # PR #3296 salvage (status: provider label honors config.yaml model.base_url, not just OPENAI_BASE_URL env)