Salvage of #29404 by @adybag14-cyber onto current main.

Summary

Termux-gated cold-start optimizations. Desktop/CI startup paths are unchanged.

Changes

• hermes_cli/main.py: new _is_termux_startup_environment() helper; model catalog top-level import (from hermes_cli.models import _PROVIDER_MODELS) deferred on Termux into the handlers that need it (kept eager on desktop/CI); new _tui_need_rebuild() mtime check on TUI source/config inputs; Termux skips npm run build when dist/entry.js is fresh; new _try_termux_fast_tui_launch() parses lightweight top-level parser for unambiguous hermes --tui / hermes chat --tui before building the full subparser tree; migrate added to _BUILTIN_SUBCOMMANDS.
• Tests: test_tui_npm_install.py (build-skip freshness, Termux-only gating, desktop always-builds), test_tui_resume_flow.py (fast-launch happy path, help fallback, non-Termux fallback).

Validation

• 78/78 targeted tests pass (test_tui_npm_install.py + test_tui_resume_flow.py + test_startup_plugin_gating.py).
• Cherry-picks cleanly on current main.
• python -m hermes_cli.main --version on desktop unchanged.
• Verified the deferred top-level import (hermes_cli.models) pulls requests (~29ms) + agent.models_dev (~42ms) via python -X importtime on desktop; on a Pixel 5 Termux this is the load-bearing piece for the bare hermes CLI startup win.

Note

Closes #29404. Reported by community user on Termux/Android (Pixel 5) — "hermes" command takes 10-15s to start. The fast TUI launch path only helps --tui invocations; bare hermes/hermes chat startup benefits from the model catalog deferral only (~500ms-1s win, not a full fix for 15s startup).

Infographic