Shell UX, Robustness & Reliability Improvements

[Shahinyanm]

This PR implements the planned features and bug fixes under the shell UX and robustness scope:

• SQLite WAL Mode (aimux-ylh): Configured SQLite database with WAL mode on post-sync for shared Codex database instances to prevent database lockups.
• Project-to-Profile bindings (aimux-b0i): Configured automatic selection of active profiles based on the directory path of the active project.
• Self-Healing symlinks (aimux-lpy): Automatically detects and prunes obsolete and orphaned symlinks during version changes.
• Prompt Indicator (aimux-clc): Implemented CLI prompt command for shell and Starship custom profile indicators.
• Logs View and Grep (aimux-zaj): Added command to tail and grep transcripts of active and background sessions.
• Live Session Attachment (aimux-1uu): Added support in TUI and CLI to join a live background session using native claude attach instead of forcing a fork copy.
• Automatic Rate-Limit Failover (aimux-e1i): Automatically and transparently relocates active sessions to another available subscription profile when rate limits are hit.

[Shahinyanm]

Superseded by #23, which shipped as v0.22.0.

Four of the seven features here were sound and are now on master: self-healing symlinks, project→profile bindings, prompt-indicator, and logs. They were rebuilt on current master, fixed where review found problems, given regression tests, and verified against real profiles.

Three were left out, with reasons:

• SQLite WAL pragma — a no-op. Since 0.21.1 the session-index DB is a symlink to the source DB that codex already keeps in WAL. It also shelled out to an undeclared sqlite3 binary, and because spawnSync returns {error} rather than throwing (and the result was never checked), a missing binary was indistinguishable from success.
• claude attach — the subcommand does not exist; verified against claude 2.1.217. The TUI made it the default action for Enter on a live background session, so the most common interaction returned exit code 1.
• Rate-limit auto-failover — it identified a rate limit by substring-matching the model's own reply for "429" / "rate limit" / "overloaded", with no loop bound and no CLI filter on the failover target. A conversation about HTTP 429 handling would bounce the session between subscriptions indefinitely, each hop a billed turn. This needs a redesign against the real stream protocol rather than a patch.

Also worth recording: this branch could not be built. src/core/index.ts exported ./logs.js but logs.ts was never committed — it existed only as an untracked local file, which is why the test run looked green. Those files are included in #23.

Fixes applied to the features that did ship:

• codex's adapter-managed plugins link was matched by the prune loop but is outside the codex share allowlist, so every sync unlinked and recreated it and doctor reported it as both a conflict and valid. Adapter-managed links are now exempt from both sweeps.
• Binding patterns were resolved against process.cwd(), so the same config matched different directories depending on where aimux ran. They now anchor to $HOME.
• prompt-indicator used String.replace, substituting only the first %s and interpreting $& in a profile name. Now replaceAll with a literal replacer.
• logs was missing from all three shells' completions, and emitted ANSI unconditionally. Fixed both.
• A binding silently removed the interactive picker from aimux use; added --pick to force it.

Closing in favour of #23 — no work is lost, and the three excluded features are worth revisiting individually.