std: full namespace tail — fs/process/socket/json/cli/hash/test

With 0115's own-wins globals landed, the remaining tail modules join
std.sx: every '#import "modules/std.sx"' now carries mem/xml/log/fs/
process/socket/json/cli/hash/test as namespaces (trace stays a direct
import).

Enablers in the same change:
- emit: dead-global elimination — a plain-data global no instruction
  references is not emitted, so tail modules' data (hash's 64-entry K
  table, OS/ARCH/POINTER_SIZE) stays out of binaries that don't use it.
  Comptime-backed globals keep their #run evaluation. 37 pinned IR
  snapshots regenerated (dead globals dropped + string renumbering from
  the larger module).
- 1055/1056 stop pinning the global error-tag ordinal (it shifts with
  program composition); they assert nonzero + tag identity + name.
- specs/readme/CLAUDE.md tail docs updated.

specs.md

@@ -2596,8 +2596,9 @@ main :: () -> s32 {
 ```
 modules/std.sx        the prelude — print/format, string ops (concat, substr,
                       path_join, ...), List(T), Context + push, the Allocator
-                      protocol; plus the namespace tail:
-                      mem / xml / log :: #import "modules/std/<m>.sx"
+                      protocol; plus the namespace tail: mem / xml / log /
+                      fs / process / socket / json / cli / hash / test ::
+                      #import "modules/std/<m>.sx"
 modules/std/          mem.sx (CAllocator, GPA, Arena, TrackingAllocator),
                       fs.sx, process.sx, socket.sx, json.sx, cli.sx, hash.sx,
                       xml.sx, log.sx, trace.sx, test.sx
@@ -2612,9 +2613,9 @@ modules/gpu/, modules/ui/   GPU protocol + retained UI toolkit
 ```
 
 `#import "modules/std.sx"` gives every prelude name bare, plus `mem.GPA`,
-`xml.escape`, `log.warn`, ... through the carried namespace tail (see
-Namespace Alias Carry). The remaining `std/` modules are imported directly
-(`#import "modules/std/json.sx"`) until they join the tail.
+`json.parse`, `fs.exists`, `hash.sha256_hex`, `log.warn`, ... through the
+carried namespace tail (see Namespace Alias Carry). Direct file imports
+(`#import "modules/std/json.sx"`) remain available for bare access.
 
 ---