§H.12 step 13: blk_meta_t flags bit constants

BLK_FLAG_CLAIMED/BLK_FLAG_MIGRATING/BLK_FLAG_STALE (bits 0/1/2), matching
the decided §F.4/§H.6 layout. Orthogonal bits, not a mutually-exclusive
enum.

Verified 3-arch boot to ok> (amd64/aarch64/riscv64).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

FABRIC-3.md

@@ -4059,7 +4059,10 @@ work, not new invention.
   comment to point at the assert instead of repeating the wrong number. Did not touch
   `BLK_META_PER_BLOCK` itself — out of scope, unused, not what this step asked for.
   Verified 3-arch boot to `ok>` (amd64/aarch64/riscv64).
-- [ ] **13.** Define the three `flags` bit constants (`CLAIMED`=0/`MIGRATING`=1/`STALE`=2).
+- [x] **13. DONE 2026-09-03.** `BLK_FLAG_CLAIMED`/`BLK_FLAG_MIGRATING`/`BLK_FLAG_STALE`
+  (bits 0/1/2, `1ull << n`) defined in `block_subsystem.h` right above `blk_meta_t`, `flags`
+  field comment updated to point at them. Verified 3-arch boot to `ok>`
+  (amd64/aarch64/riscv64).
 - [ ] **14.** Add C get/set accessors for the new fields in `block_subsystem.c`.
 - [ ] **15.** Add FORTH wrappers (`BLK-ACL-ALLOW@`/`!`, `BLK-ACL-TTL@`/`!`, `BLK-OWNER@`).
 - [ ] **16.** Add a new policy capsule (mirroring `ACL.4th`) with a real fast-deny check on

capsules/BLOCK_MAP.md

@@ -1,5 +1,5 @@
 # Capsule Block Manifest — Auto-generated
-<!-- Generated by mkcapsule --manifest  2026-09-03T11:16:49Z -->
+<!-- Generated by mkcapsule --manifest  2026-09-03T11:21:56Z -->
 <!-- DO NOT EDIT — re-run mkcapsule --manifest to refresh.  -->
 <!-- Hand-written justifications and immutability notes live  -->
 <!-- in MANIFEST.md alongside this auto-generated index.      -->

include/block_subsystem.h

@@ -199,6 +199,16 @@ typedef struct {
 _Static_assert(sizeof(blk_volume_meta_t) == 4096,
                "blk_volume_meta_t must be exactly one 4 KiB devblock");
 
+/* blk_meta_t.flags bit values -- FABRIC-3.md §F.4/§H.6/§H.12 step 13,
+ * decided 2026-09-02/03. Orthogonal bits, not a mutually-exclusive enum:
+ * a block can be both CLAIMED and MIGRATING at once. Grounded in the only
+ * states §F.4 actually motivated by a real need (MIGSM/UNCLEAN, two
+ * then-currently-blocked graph nodes) plus CLAIMED/STALE, the names
+ * already used loosely in that pass's own prose. 61 bits remain reserved. */
+#define BLK_FLAG_CLAIMED   (1ull << 0) /* owned, per BMAPFMT's owner_fp */
+#define BLK_FLAG_MIGRATING (1ull << 1) /* mid-migration; serves MIGSM */
+#define BLK_FLAG_STALE     (1ull << 2) /* interrupted flush; serves UNCLEAN */
+
 /* Per-1 KiB block metadata (packed into top 1 KiB region of each 4 KiB sector). */
 typedef struct {
     /* Core integrity (16 bytes) */
@@ -210,7 +220,7 @@ typedef struct {
     uint64_t modified_time; /* Unix timestamp (last write) */
 
     /* Block status (16 bytes) */
-    uint64_t flags; /* Status flags */
+    uint64_t flags; /* Status flags -- BLK_FLAG_* bits above */
     uint64_t write_count; /* Number of writes (wear leveling) */
 
     /* Content identification (32 bytes) */