fix(bitcoin): bulletproof multi-version switching (Knots & Core)

Three stacked bugs made "switch version" silently fail / crash-loop, and
the data-access mismatch corrupted a node's index during recovery attempts.

Backend renderer:
- sync_quadlet_unit ignored the per-app pinned version and re-rendered the
  quadlet with the manifest's :latest every reconcile tick, reverting any
  switch. Factor the install-time catalog/pin resolution into a shared
  resolve_catalog_image() and call it in BOTH install_fresh and
  sync_quadlet_unit.
- The renderer folded manifest `entrypoint: ["sh","-lc"]` into Exec=, which
  only worked when the image entrypoint was a passthrough shell wrapper. The
  versioned images use ENTRYPOINT ["bitcoind"], so Exec=sh -lc ... became
  `bitcoind sh -lc ...` and crash-looped. Emit a real Entrypoint= override;
  exec_changed now also compares Entrypoint=.

Images:
- Build all bitcoin images (Core + Knots, every version) as container-root
  (USER removed) like the legacy :latest image. Chain data is owned by the
  data_uid (container uid 102); root reads it via CAP_DAC_OVERRIDE (granted in
  the manifest). A non-root USER (the previous uid 1000) can't read existing
  chain data → "Error initializing block database". Still fully rootless:
  container-root maps to the unprivileged host service user.

Catalog:
- bitcoin-knots versions[]: 29.3.knots20260508/20260507/20260210 +
  29.2.knots20251110, "latest" tracking newest.
- bitcoin-core versions[]: add 29.2 + a "latest" entry. All images rebuilt
  root and published to the mirror.

Frontend:
- AppSidebar version dropdown: rename the latest option to "Always use the
  latest version" (no v prefix), fix right padding, and guarantee the current
  selection matches a real option (was rendering blank).
- New InstallVersionModal: full-screen version chooser shown from the App
  Store / Discover install button for multi-version apps (Bitcoin Knots/Core),
  app icon + "Install <name>", latest pre-selected.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

releases/app-catalog.json

@@ -334,7 +334,7 @@
       }
     },
     "bitcoin-core": {
-      "version": "28.4.0",
+      "version": "latest",
       "manifest": {
         "app": {
           "id": "bitcoin-core",
@@ -343,7 +343,7 @@
           "description": "Reference Bitcoin Core node with dynamic prune/full-mode startup based on host disk.",
           "container_name": "bitcoin-core",
           "container": {
-            "image": "146.59.87.168:3000/lfg2025/bitcoin:28.4",
+            "image": "146.59.87.168:3000/lfg2025/bitcoin:latest",
             "pull_policy": "if-not-present",
             "network": "archy-net",
             "entrypoint": [
@@ -433,6 +433,11 @@
         }
       },
       "versions": [
+        {
+          "version": "latest",
+          "image": "146.59.87.168:3000/lfg2025/bitcoin:latest",
+          "default": true
+        },
         {
           "version": "31.0",
           "image": "146.59.87.168:3000/lfg2025/bitcoin:31.0"
@@ -445,10 +450,13 @@
           "version": "29.3",
           "image": "146.59.87.168:3000/lfg2025/bitcoin:29.3"
         },
+        {
+          "version": "29.2",
+          "image": "146.59.87.168:3000/lfg2025/bitcoin:29.2"
+        },
         {
           "version": "28.4.0",
-          "image": "146.59.87.168:3000/lfg2025/bitcoin:28.4",
-          "default": true
+          "image": "146.59.87.168:3000/lfg2025/bitcoin:28.4"
         },
         {
           "version": "27.2",
@@ -569,12 +577,24 @@
       "versions": [
         {
           "version": "latest",
-          "image": "146.59.87.168:3000/lfg2025/bitcoin-knots:latest",
+          "image": "146.59.87.168:3000/lfg2025/bitcoin-knots:29.3.knots20260508",
           "default": true
         },
         {
           "version": "29.3.knots20260508",
           "image": "146.59.87.168:3000/lfg2025/bitcoin-knots:29.3.knots20260508"
+        },
+        {
+          "version": "29.3.knots20260507",
+          "image": "146.59.87.168:3000/lfg2025/bitcoin-knots:29.3.knots20260507"
+        },
+        {
+          "version": "29.3.knots20260210",
+          "image": "146.59.87.168:3000/lfg2025/bitcoin-knots:29.3.knots20260210"
+        },
+        {
+          "version": "29.2.knots20251110",
+          "image": "146.59.87.168:3000/lfg2025/bitcoin-knots:29.2.knots20251110"
         }
       ]
     },