feat: SSH dev routing, model registry UX, chat input toolbar, doc sync

Backend / infrastructure:
- cortex/tools/_projects.py (new): shared project alias registry with ssh_host
  for workstation projects (aether_api, aether_frontend, aether_container)
- cortex/tools/git.py: all git tools route to workstation via SSH when ssh_host set
- cortex/tools/aider.py: aider_run SSH-routes to workstation using bash -l -c
- cortex/routers/local_llm.py: POST /api/models/{id}/edit AJAX endpoint — save
  model edits without page reload or tab reset; returns JSON {ok, label, model_name}
- cortex/llm_client.py: remove Gemini CLI and Claude CLI backends; clean up
  fallback chain and process group tracking (continuation of Gemini CLI removal)
- cortex/routers/auth.py: strip Claude/Gemini CLI auth status checks (CLI removed)
- cortex/routers/chat.py: remove legacy claude/gemini backend fields
- cortex/config.py: clean up CLI-related settings
- cortex/main.py: remove CLI lifecycle hooks

UI:
- cortex/static/local_llm.html: model edit forms now save via fetch() + toast;
  stay on Models tab; update row header label in place on success
- cortex/static/index.html: restructure input area to column layout — textarea
  above, compact toolbar below (Chat/Tools/Attach + Send); fixes dead space at
  M/L/XL sizes; context panel "Role" → "Model" section label
- cortex/static/style.css: column input-area layout; #input-toolbar; flex:1 →
  width:100% on textarea (fixes scrollHeight in column flex context); compact
  send/stop button padding
- cortex/static/app.js: add XL (720px) to height cycle; default M (240px)

Docs:
- cortex/static/HELP.md: S/M/L → S/M/L/XL; add Rebuild to distill table; fix
  "Role selector" references (no such UI); fix "your active role" → Chat role;
  fix ⚡ toggle description; Model Registry section cleanup
- documentation/ARCH__BACKENDS.md: reflect CLI removal, current backend state

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/tools/_projects.py

@@ -0,0 +1,31 @@
+"""Shared project alias registry for Cortex tools."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass
+class ProjectDef:
+    path: str       # path on the host where the project lives (~ is expanded at runtime)
+    ssh_host: str = ""  # if set, git/aider commands run via SSH on this host
+
+
+_CORTEX_ROOT_STR: str = str(Path(__file__).parent.parent.parent.resolve())
+
+PROJECT_ALIASES: dict[str, ProjectDef] = {
+    "cortex": ProjectDef(path=_CORTEX_ROOT_STR),
+    "aether_api": ProjectDef(
+        path="~/OSIT_dev/aether_api_fastapi",
+        ssh_host="scott-wks-main-i7",
+    ),
+    "aether_frontend": ProjectDef(
+        path="~/OSIT_dev/aether_app_sveltekit",
+        ssh_host="scott-wks-main-i7",
+    ),
+    "aether_container": ProjectDef(
+        path="~/OSIT_dev/aether_container_env",
+        ssh_host="scott-wks-main-i7",
+    ),
+}