First entries of the encode-coverage effort. Adds CCMP_REG/CCMN_REG (W/X) to ENCODING_TABLE with llvm-mc-verified bit patterns; the table metaprogram regenerates the encode/decode blobs and the typed builders auto-generate (inst_ccmp_reg/inst_ccmn_reg).
Verified: encode matches llvm-mc (CCMP X1,X2,#3,EQ=0xFA420023; CCMN W5,W6,#7,NE=0x3A4610A7), decode round-trips, arm64 check+tests pass. Needs no encoder change (reuses RN/RM/NZCV_FIELD/COND_HI). The imm5 forms (immediate at bits 20:16) need a new Operand_Encoding and follow separately.
Workflow proven: llvm-mc as the encoding oracle -> SoT entry -> regen -> builder auto-generates -> verify.
Each ISA's hand-written ENCODING_TABLE (the single source of truth) now lives
in a per-arch tablegen/ metaprogram that flattens it and serializes committed
binary blobs; the library #loads those into @(rodata) at compile time rather
than compiling a table body. No arch keeps encoding_table.odin or
decoding_tables.odin -- only a generated tables.odin loader and tables/*.bin.
* Two-stage, type-checked pipeline: tablegen Stage A emits human-readable
generated Odin, which compiles and serializes the blobs in Stage B.
* encode() goes through encoding_forms(m); decoders are unchanged apart from
x86's flattened 2-D index. Decode tables are byte-identical to the old ones.
* build.lua: a LuaJIT driver for the metaprograms, validations, and tests,
with cross-platform gating and a clear report.
* Docs refreshed; the obsolete forward-looking plan in cross_arch_design.md
trimmed to what was actually built.
* Attribution headers added to all rexcode source files; the generators emit
them so generated files keep them.
