G1 step 2: Gemini parsers (host-tested), and the memory decision (Q86)

lib/gemini: URLs split per RFC 3986 appendix B and resolved per section
5.2 (all 32 reference examples of 5.4 pass, with gemini:// for http://),
the request form (no fragment, lower-case host, never an empty path),
query encoding for input prompts, Saved Page paths; the response header
(status, category, MIME type and parameters, 1024-byte meta limit);
gemtext's line types; and display text for the Latin-1 fonts. 12 tests.

Q86, decided after step 1: free heap stays above 40 KB in steady state
and 20 KB during a handshake; a fetch won't start below 55 KB.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

docs/milestones/G1.md

@@ -23,6 +23,7 @@ Gemini (geminiprotocol.net): one request per TLS connection on port 1965, the re
 | Q82 | `s` saves the page on screen as a **Saved Page**: `/gemini/saved/<host>/<path>.gmi`, the gemtext as received plus a first line with its URL and save date. Saving again replaces it, and says so. |
 | Q83 | `S` saves the page and the pages it links to, one level deep: gemtext only, same host only, at most 30 pages, in the background with a progress Toast. |
 | Q84 | The start page lists Saved Pages, newest first, grouped by capsule; they open with no network. In a Saved Page, a link to another Saved Page opens the saved copy; other links fetch online if Wi-Fi is up, or say "not saved, offline". A Saved Page shows when it was saved; `r` refreshes it. |
+| Q86 | *Decided after step 1.* **Two floors:** free heap stays above 40 KB in steady state, and above 20 KB for the second or two of a TLS handshake (measured: 24 KB with IRC connected). A fetch refuses to start below **55 KB** free ("not enough memory: stop IRC or retry"), so nothing pushes lower. |
 | Q85 | Saved Pages are deleted from the App only (`d`, with confirmation), never by Storage Clean-up's age rules, like Notes. |
 
 ## Measured (step 1)