Dogfood a repo architecture diagram into TECHNICAL.md; fix arch alt reproducibility

TECHNICAL.md

@@ -172,3 +172,7 @@ There is no service to restart, no rollback beyond `npm uninstall -g codeshot` /
 - A cyclic call graph (recursion, or A and B calling each other) can cause `--depth`'s transitive traversal to rediscover the root symbol or an already-drawn depth-1 node as a "from"/"to" endpoint of a deeper edge. This is harmless (graphviz just draws the extra edge; `dedupeEdges` still collapses exact repeats) but can occasionally show what looks like a redundant edge back into an already-visible node.
 - **`--architecture` mode's edges can be misattributed to the wrong file when symbol names collide.** `codegraph callees <name>` takes a bare name with no way to disambiguate which file's symbol is meant (unlike `codegraph node -f <file>`, which does support this). In symbol mode this ambiguity affects exactly one user-chosen name — a corner case. In `--architecture` mode, Codeshot probes `codegraph callees` for every enumerated symbol in the whole repo, where generically-named methods (`render`, `init`, `get`, `run`, `String`) existing in more than one file is common, not rare, in most real codebases (confirmed: 12 duplicate names out of 500 probed symbols on a real ~1,900-node Go repo). `duplicateNameWarning` surfaces this on stderr with real examples from the current run, but Codeshot has no way to fix the underlying ambiguity — same as the other `codegraph` indexing gaps documented above, it can only draw what `codegraph` returns.
 - **`--architecture` mode's enumeration query (`codegraph query --json --limit <big> -- ''`) has confirmed, inconsistent `--limit` behavior worth knowing before trusting it.** Without `--limit`, an empty-string query silently caps around 50 results regardless of actual repo size (confirmed on a real 1,870-node index). Passing a large `--limit` (confirmed with both 500 and 2000 against that same index) instead returns *every* result codegraph has — more than the requested number, not capped at it. Codeshot works around this by always passing a very large `--limit` to force the "return everything" behavior, then applying the real `--max-symbols` cap client-side — but the *order* codegraph returns results in in that case is unknown (untested whether it's insertion order, alphabetical, ID-based, or something else), so on a repo larger than `--max-symbols`, the kept subset should not be assumed to sample evenly across the whole repo — it could be clustered by file, directory, or however codegraph happens to have stored them.
+
+<!-- codeshot:arch:start -->
+![Architecture — generated by codeshot](docs/architecture.svg)
+<!-- codeshot:arch:end -->

render/callgraph.js

@@ -768,7 +768,13 @@ async function main() {
 
   if (values.architecture) {
     const dot = await runArchitectureMode(repoPath, { limit, maxSymbols, maxRender });
-    const alt = `${path.basename(path.resolve(repoPath))} architecture — generated by codeshot`;
+    // Fixed, path-independent alt: deriving it from the checkout's directory
+    // basename made the embedded markdown vary by where the repo was cloned
+    // (a bare-worktree dir, "master", a branch name...), which both read wrong
+    // and broke --check portability — a fresh clone under a different dir name
+    // would report the committed diagram as drifted. The repo name is redundant
+    // anyway; the diagram lives in that repo's own doc.
+    const alt = 'Architecture — generated by codeshot';
     finishOutput(dot, { format, outFile, embedFile, check: values.check, markerId: 'arch', alt });
     return;
   }

test/run.js

@@ -734,6 +734,11 @@ test('CLI --embed --architecture round-trips: writes image + block, --check then
     const md = fs.readFileSync(doc, 'utf8');
     assert.match(md, /<!-- codeshot:arch:start -->/);
     assert.match(md, /!\[[^\]]*generated by codeshot\]\(codeshot-arch-[^)]+\.svg\)/);
+    // The arch alt must be path-independent (not the checkout dir basename), so
+    // the embedded markdown is reproducible across clones and --check is stable.
+    // Before the fix it was `<basename(repoRoot)> architecture — ...`.
+    assert.match(md, /!\[Architecture — generated by codeshot\]/);
+    assert.doesNotMatch(md, new RegExp(`!\\[${path.basename(path.resolve(repoRoot))} architecture`), 'alt must not leak the checkout dir name');
     const imgName = md.match(/\]\((codeshot-arch-[^)]+\.svg)\)/)[1];
     assert.ok(fs.existsSync(path.join(dir, imgName)), 'expected the image written next to the doc');