feat(sources): removing a source deletes its files and index entries behind a confirmation modal

README.md

@@ -137,10 +137,16 @@ uv run uvicorn app.main:app --reload
   missing/relative path is rejected, naming the path; so are duplicates)
   — since phase 49 this is an API-only operation (`POST /api/git-sources`
   with `kind=local`; the page's form was replaced by the upload form). List
-  rows carry a **Git** or **Local** badge. Adding/removing does not clone
-  or prune on its own: the Sync button performs that (git + local together,
-  one run, prune over the union), and a removed source's documents leave
-  the index on the next sync.
+  rows carry a **Git** or **Local** badge. Adding does not clone: the
+  Sync button performs that (git + local together, one run, prune over
+  the union) and still prunes **upstream file churn** — a file deleted
+  in a repo or dropped from a local directory leaves the index on that
+  run. **Removing a source is a total removal, done immediately** — a
+  confirmation modal states it first, then the source's entry, all of
+  its indexed documents, and — for git clones and uploaded archives —
+  its files on disk (the checkout under `BOR_SOURCES_DIR` or the
+  unpacked folder under `BOR_UPLOAD_DIR`) are gone in one action; files
+  in the owner's own local directories are never touched.
 
 ## Thinking
 
@@ -406,9 +412,12 @@ table** (the `git_sources` registry with a `kind` discriminator: `git` |
   as a failing git clone).
 - **Pruning is over the union** — git checkouts and local directories are
   imported together with `prune=True`, so a file removed from a local
-  directory, a repo, or a removed source leaves the index on that run.
-  Removing the row on the page stops the directory being a source; its
-  documents leave the index on the next sync (exactly like git sources).
+  directory or a repo leaves the index on that run (upstream file
+  churn). Removing the source on the page is a **total removal, done
+  immediately** (a confirmation modal states it first): its entry and
+  its indexed documents leave at once — but the directory itself is the
+  owner's own and is **never touched on disk** (only git checkouts and
+  uploaded archives get their files deleted).
 - **`import_docs`** (no `--source`) resolves the stored git **and** local
   rows — git cloned/pulled as above, local walked directly — in one run;
   `--source` still wins over everything; while the table is empty,