feat(intake): Themes: keyword list and theme-keyed cross-repo bundling

agents/conductors/intake/AGENTS.md

@@ -84,6 +84,15 @@ Writes the light header PyAutoMind blesses (`README.md` "Prompt file format"),
 extended with `Difficulty:/Autonomy:/Priority:`. No YAML frontmatter, no required
 schema — light structure over free-form prose.
 
+`Themes:` is written at formalisation, directly under `Repos:` and in the same
+list shape (`intake classify --themes mge,jax-gradient`, primary keyword
+first). `Target:` says where the code lives; `Themes:` says what the work is
+about, and it is what the auto-bundler groups on. The vocabulary is
+`PyAutoMind/themes.md` — a markdown list a human edits, read by `parse_themes`,
+never a second copy in here. Optional and never blocking: a prompt formalises
+with or without it, an unknown keyword still groups (⚠️ on the card, counted in
+the page's Hygiene section), and an un-themed prompt falls back to `Target:`.
+
 ## Modes
 
 | Mode | Command | What it does |
@@ -119,10 +128,26 @@ per member, one shared worktree per repo), which makes it the exact opposite of
 an epic: no order, no phase gate, and members stay in every pick list above,
 because a bundle is an additional VIEW and never a replacement. Two sources:
 **pinned** entries in `PyAutoMind/bundles.md` (plus any prompt whose header says
-`Bundle: <slug>`), and **auto** bundles this renderer computes — same target
-repo, no epic member, no declared `Blocked-by:`, no `human-required`, no
-`too-large`, packed under a size cap (`BUNDLE_*`: small 1 / medium 2 / large 4
-points, cap 8, at most one large, 2-4 members) in priority-then-path order.
+`Bundle: <slug>`), and **auto** bundles this renderer computes — no epic
+member, no declared `Blocked-by:`, no `human-required`, no `too-large`, packed
+under a size cap (`BUNDLE_*`: small 1 / medium 2 / large 4 points, cap 8, at
+most one large, 2-4 members).
+
+Auto bundles are pooled by `_pool_key`: a prompt's **primary theme** (the first
+`Themes:` bullet) when it has one — the topical key, cross-repo by design — and
+its **`Target:`** when it does not, which is what the bundler keyed on before
+themes existed, so an un-themed backlog renders exactly as it did. Every prompt
+has one key, so it lands in at most one auto bundle. Inside a pool
+`_pack_by_affinity` seeds with the most pickable member (priority, then path)
+and then adds whichever remaining candidate that still fits shares the most
+keywords with the seed (Jaccard over the whole list; ties: priority, then the
+seed's repo, then path) — so a large pool splits by what the work is about
+rather than by filename order. With no themes every overlap is 0.0 and this
+reduces, member for member, to the old priority-then-path first fit. A
+theme-keyed card is titled `<primary>` plus the keywords every member shares
+(`mge · jax-gradient`) and its members table carries a **Repo** column, because
+it is cross-repo by construction; a Target-keyed card keeps `<target> — bundle
+n` and no column, where that column would be a constant.
 The proposals are then ranked (most urgent member, then biggest session, then
 slug) and only the first `BUNDLE_LIST_MAX` reach the page, with a footer saying
 what was left off and that pinning keeps it — the same pick-list-not-inventory