feat(admin): local directory sources — kind/path on git_sources, combined sync + import, page form + badges

An existing, non-git directory is now a first-class source alongside
the git repos: one table (git_sources + kind discriminator — A13
reversible migration), one admin page, one Sync button (phase locked
decisions; the phase-35 table is extended, not duplicated). The DB is
the local-source registry — no env var for local paths;
BOR_GIT_SOURCES stays a git-only empty-table fallback.

Migration 0007 (reversible, up/down integration-tested):
git_sources.kind TEXT NOT NULL DEFAULT 'git' + ck_git_sources_kind
(kind IN ('git','local')); git_sources.path TEXT NULL +
uq_git_sources_path (mirrors 0006's uq_git_sources_url). Existing rows
read kind='git', path=NULL.

API (phase-35 contract extended, git byte-identical): POST kind=local
requires path — trimmed, ~-expanded, absolute + an existing server
directory, else 422 naming the path (fail loud at add-time); duplicate
path 409 (named); wrong field combos 422. GET rows carry kind + path
(git and env rows: path null); anonymous still 403 on every route (A10).

Sync + import_docs resolve DB git + local rows together: git →
clone_or_pull (unchanged); local → re-verified .is_dir() AT SYNC TIME
(it may have moved/deleted since add-time) — a missing dir raises
"local source missing: <path>" (sanitized) before anything imports;
one import_sources(..., prune=True) over the single combined list
(pruning covers the union). Both-empty fails loudly ("no sources
configured (git or local)"); --source still wins; the env fallback
stays git-only.

Page: second "Add a local directory" form (the same §7.4 never-stale
button + inline-error lifecycle as the git form; 422/409 details name
the path), Git/Local badges on rows (text + color, never color alone —
WCAG), updated hint (git + local together, union prune); the
anonymous sign-in gate is unchanged.

Tests: 0007 up/down; the API local-kind matrix (403/201/422/409) with
the git-kind suite green unchanged; the sync pipeline local/git/
mixed/missing against a host temp dir (the KB actually updated);
import_docs DB resolution + --source precedence. Story E2E (isolated,
deterministic across runs): add (Local badge) → missing path inline
422 naming it / duplicate 409 → the real Sync button imports the
fixture file (GET /api/docs + sentinel in its content) → file deleted
+ sync prunes it (union prune) → row removed; anonymous gate + 403s
(phase-35 regression). test_git_sources_admin.py (phase 35) green
UNCHANGED — no selector collision with the new form;
test_sync_button.py green.

Docs: README — the two managed kinds (git = clone/pull mirror; local =
direct in-place walk), add-time validation, union pruning, "the DB is
the local-source registry (no env var for local paths)";
.env.example — the env fallback is git-only.

.env.example

@@ -55,8 +55,14 @@ BOR_AGENT_READ_CALLS=1            # per-turn read_document opportunities (0 disa
 # variable is the EMPTY-TABLE FALLBACK: it only applies while the admin
 # list is empty; once the page has stored any source, this variable is
 # ignored (the page is the source of truth). Empty table + empty variable
-# = no git sources (import_docs falls back to --source / the old
-# ~/Homelab + ~/Deployments defaults; the UI Sync button fails loudly).
+# + no local rows = no sources (import_docs falls back to --source / the
+# old ~/Homelab + ~/Deployments defaults; the UI Sync button fails loudly
+# with "no sources configured (git or local)").
+#
+# Phase 38: this env fallback is GIT-ONLY. Local directory sources (an
+# existing, non-git directory on the server) have NO env var — the DB is
+# the local-source registry: add them on the same admin page (the
+# "Add a local directory" form, kind 'local' + path, migration 0007).
 # BOR_GIT_SOURCES=https://github.com/user/homelab.git,https://github.com/user/deployments.git
 # BOR_SOURCES_DIR=~/bor-sources