Add portless support

[beastyrabbit]

Summary

• Resolve remaining review conversations for portless support

Somewhere a GPU is overheating so I don't have to think.

[greptile-apps]

Greptile Summary

This PR makes Portless the default local dev experience, demoting the fixed-port setup to an explicit :fallback suffix. All four changed files are documentation or script orchestration — no application logic is touched.

Key changes:

• pnpm dev and pnpm dev:all now run via Portless (http://web.localhost:1355 / http://api.localhost:1355) instead of raw Vite on fixed ports.
• dev:server is the new canonical name for the backend script; the old server alias is removed (noted in README as a pnpm built-in name collision).
• dev:web:fallback / dev:server:fallback / dev:all:fallback added for developers who prefer fixed ports.
• Old *:portless aliases are kept as pass-throughs for backward compatibility.
• APP_ORIGIN=http://web.localhost:1355 is now threaded into the server script, which is important for CORS/origin checks in portless mode.
• dev:old:all correctly updated to use dev:web:fallback (fixed ports) rather than the new portless dev command.
• All three docs files (CLAUDE.md, README.md, AGENTS.md) are consistent with each other and with the new script layout.

Confidence Score: 5/5

• Safe to merge — changes are limited to script aliases and documentation with no application logic affected.
• All changes are dev-workflow scripts and docs. Old :portless aliases are preserved for backward compat, fallback variants are added for flexibility, and the three doc files are mutually consistent. No runtime code is modified.
• No files require special attention.

Important Files Changed

Filename	Overview
package.json	Promotes portless to the default dev workflow; removes server script alias, adds dev:web, dev:server, and *:fallback variants; old *:portless aliases preserved for backward compat.
CLAUDE.md	Documentation updated to reflect portless as default; fixed-port setup moved to dev:all:fallback; URL resolution section updated accordingly.
README.md	Quick-start section updated to match new portless-default workflow; fallback and portless descriptions swapped/clarified.
AGENTS.md	Tooling section updated: pnpm server replaced by pnpm dev:server, new *:fallback scripts added.

_{Reviews (1): Last reviewed commit: "fix: resolve remaining review conversati..." | Re-trigger Greptile}