docs: fix four broken README links and the ambiguous catalog-seeding wording

[cliffhall]

Summary

Four relative links in the client READMEs point at files that do not exist on v2/main, and the launcher README describes catalog seeding in a way that reads as one behavior when it is actually two.

The broken links

README	Link	Status
clients/cli/README.md	../../docs/mcp-server-configuration.md	missing
clients/tui/README.md	../../docs/mcp-server-configuration.md	missing
clients/tui/README.md	../../docs/images/tui-screenshot.png	missing (broken image at the top of the page)
clients/launcher/README.md	../../docs/launcher-config-consolidation-plan.md	missing

Why they're broken

All three targets exist on v1.5/main and were never carried over. v1.5/main is not an ancestor of v2/main — the clients were merged across but the repo-root docs/ folder was not, so the READMEs arrived still referencing it. docs/ on v2/main contains only mcp-app-review.md, which was added later and independently.

This is not cosmetic for two of them: both the cli and tui READMEs delegate their entire "MCP server (which server to connect to)" options section to mcp-server-configuration.md rather than documenting --catalog / --config / --server / -e / --cwd / --header / --transport / --server-url / [target...] themselves. Following the link is currently the only way to find that reference, and it 404s — so that flag surface is effectively undocumented in-repo for two of the three clients.

The seeding ambiguity

clients/launcher/README.md describes a missing writable catalog as "created/seeded if missing" in both its --web table and its --cli/--tui table, which reads as one shared behavior. It is two:

• Web seeds DEFAULT_SEED_CONFIG (core/mcp/serverList.ts) — filesystem-server-default (server-filesystem /tmp) and everything-server-default — so a first launch has something to connect to.
• CLI / TUI seed an empty { "mcpServers": {} } (seedEmptyCatalog in core/mcp/node/config.ts).

Verified by running each surface against a throwaway HOME. clients/cli/README.md already says "seeded empty", which is right for the CLI but compounds the confusion when read next to the launcher's undifferentiated wording.

This one has already misled a reader: it produced a wrong claim in the modelcontextprotocol.io Inspector docs (#1803), caught in review.

Proposed fix

• Write a fresh docs/mcp-server-configuration.md for v2. Do not restore the v1.5 file — it predates the --catalog / --config split (writable-and-seeded vs. read-only-and-errors), MCP_CATALOG_PATH, and the mutual-exclusivity rules, so restoring it verbatim would document a model that no longer exists.
• Restore docs/launcher-config-consolidation-plan.md from v1.5/main with its path references corrected (launcher/ → clients/launcher/). Its substance — single process, no spawn(), shared config processor in core/mcp/node/config.ts — still holds, and it is the rationale the launcher README's Architecture section points at.
• Regenerate docs/images/tui-screenshot.png against the current TUI rather than restoring the v1.5 image, which shows an older UI.
• Split the seeding rows in the launcher README so the web and cli/tui behaviors are stated separately, with the seeded contents shown.

Acceptance

• No broken relative links in any README (README.md, AGENTS.md, clients/*/README.md, docs/*.md).
• The cli and tui READMEs' server-options sections resolve to real content.
• The launcher README states the two seed behaviors distinctly.

[cliffhall]

Fixed by #1812 (merged as 4d30d1c). Auto-close does not fire for PRs targeting v2/main, so closing manually.