Keep a fixed minimal tool wire with free-name dispatch

[TheGreatAxios]

Summary

• Fixed wire tools array never grows mid-session (provider tools-prefix cache stays hot)
• Wire membership is minimal: file/shell loop + product loop tools + only harness-blocked substitutes (grep, search_files, web_fetch, web_search)
• Deferred tools (list_dir, lsp, present, MCP) stay registered and dispatchable by exact name without wire promotion
• tool_search returns schema cards only — no promote/activate path
• System prompt only requires tools that are already on the wire
• Stops Grok 4.6 thrash on capability web-bait (clean 3-turn web_fetch path)

Test plan

• bun run typecheck / pre-commit build
• Unit: tool-search, prompts, director (wire stability + free-name)
• Capability: web-bait matrix on xai/thegreataxios for grok-4.5, grok-4.6, grok-composer-2.5-fast — 3/3 pass, all use web_fetch, 3 turns, no thrash

Notes

Linear ticket creation is blocked on a hung Linear MCP in this session; will attach CL-#### once the issue exists and rename the branch if needed.

[TheGreatAxios]

Hold — zero-regression review BLOCK.

Fleet review found that this PR removes wire promotion that main treated as required for strict providers (Grok Responses / Codex / OpenAI-style). Client free-name dispatch works, but undeclared MCP/list_dir/lsp/present tools often will not be emitted by strict models after tool_search.

Before ship, need one of:

1. Restore promotion for non-built-ins (MCP) after search, or
2. Prove those providers emit undeclared free-name tools, or
3. Explicit product cut documented as best-effort MCP on strict providers.

Not merging as part of the current train.

[TheGreatAxios]

Close as abandoned experiment. Main already ships web_fetch/web_search on the catalog wire (the web-bait win). The no-promote/free-name design is incompatible with 0.2.99 same-turn MCP dispatch and current promoteTools. Remaining cache-growth work belongs on existing CL-1860 (evict after promote), not a revival of this branch. Do not merge.