feat(output): support declarative column formats

[samzong]

What is changed?

• Add declarative column_formats for currency, fixed-point source scaling, grouping, and fraction bounds.
• Preserve exact scaled values without floating-point conversion and keep JSON, YAML, and raw output unchanged.
• Expose column labels and formats through catalog schema 19 and bump the generated runtime schema.
• Add overlay validation, code generation, runtime formatting, catalog round-trip coverage, and usage documentation.

Why

• Let downstream generated CLIs produce readable monetary tables entirely through overlays, without application-specific renderers.

Verification

• make check
• go test -race ./...
• go test -race -count=1 ./pkg/runtime ./internal/codegen/render ./internal/overlay
• Generated and built a Tokener scratch CLI, then verified catalog metadata and live currency table output.

[codspeed-hq]

Merging this PR will degrade performance by 48.38%

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

❌ 21 regressed benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	yaml	2.5 ms	5.2 ms	-52.25%
❌	BenchmarkBuildFlat	929.1 µs	1,941 µs	-52.13%
❌	large	1.2 ms	2.4 ms	-49.93%
❌	BenchmarkFindCatalogCommand	4.4 µs	8.7 µs	-49.9%
❌	large	804.3 µs	1,602.5 µs	-49.81%
❌	BenchmarkCatalogJSON	1.5 ms	3 ms	-49.7%
❌	yaml-large	8.1 ms	16 ms	-49.29%
❌	small	98.5 µs	194.3 µs	-49.28%
❌	miss	1.9 ms	3.7 ms	-49.25%
❌	hit	1.9 ms	3.8 ms	-49.23%
❌	json-large	1.7 ms	3.3 ms	-48.78%
❌	small	73.8 µs	143.7 µs	-48.67%
❌	json-small	130.6 µs	253.6 µs	-48.52%
❌	BenchmarkFormatTableInferredColumns	483 µs	938.1 µs	-48.51%
❌	BenchmarkParseNormalize	3.2 ms	6.2 ms	-48.28%
❌	table	382.5 µs	730.1 µs	-47.61%
❌	small	67.2 µs	127.8 µs	-47.41%
❌	json	693.7 µs	1,287.3 µs	-46.11%
❌	large	692.5 µs	1,279.7 µs	-45.88%
❌	small	55.2 µs	99.8 µs	-44.71%
...	...	...	...	...

ℹ️ Only the first 20 benchmarks are displayed. Go to the app to view all benchmarks.

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing feat/column-formats (dbf2a69) with main (8ab1b86)}