An anchor printed before a part split later resolves to another part and reports exact #2710

Written-by: Chief

core/src/host/chat-index.js:225 (anchorOf) prints an anchor as #<seq> while the chat has one part and as part N #<seq> only afterwards; :305 (aroundOwnChat) resolves a bare #<seq> to parts[parts.length - 1] — the part that is current now, not the part the anchor was printed from. Once parts.js:973 ends a segment and a fresh part becomes current, every bare anchor a Bot saved and quoted back resolves into the wrong part, and the lookup reports success.

Reproduction (main f36a3e024024541bc141ad27a8ebcfe6e37b6e80)

/data/dsh/bot/workspace/audit47/repro/chat-index-truth.test.mjs, test divergence: an anchor printed without a part number resolves to another part (real chat-index.js, temp home, real chat-index.sqlite, fake Session log):

• part 1 holds seq 2 = "the url is https://example.test/xyz keep it"; the anchor printed at that moment is #2;
• a segment ends and part 2 becomes current;
• read_own_chat around "#2" returns part 2's seq 2 and says exact: true.

Control in the same file: the same lookup written as "part 1 #2" reaches the real source. That is also the one-line fix — always print the part number.

Why it matters

The anchor is the tool's own citation: a Bot quotes [#2 · 10-08 14:22] in its answer and later looks it up to check what it said. With the bare form it silently gets a different message from a different part and cannot tell — exact: true is the worst possible answer here. A conversation that grew past its first part is the normal case, not an edge.

Expected

anchorOf always prints part N #<seq> (the form aroundOwnChat already resolves exactly), so an anchor names the part it came from from the first message onward. A bare #<seq> in an older anchor keeps resolving as it does today for compatibility, and the reader says so when it had to guess rather than claiming exact.

Change scope

core/src/host/chat-index.js (anchorOf, and aroundOwnChat's fallback so a guessed part is not reported as exact), the tests in core/test/ that assert the current anchor text, and any doc line that shows the anchor format.