honor inline license.text in recipes

[jorgeMFS]

Adds an optional license.text field to the recipe schema. When a recipe sets it, the hub stores that text verbatim as the LICENSE artifact in the registry instead of fetching one from the upstream repo. This unblocks recipes for tools whose upstreams carry the license in a source-file header rather than a standalone LICENSE file (lh3/wgsim is the immediate motivating case, but the same shape applies to plenty of small bioinformatics utilities).

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Merge order

sbom-implementation is the priority branch and rewrites parts of the builders. This PR conflicts with it on hub/builders/builder.py and hub/validate/validate.py. Rebase after it lands.

Also worth a look: this targets dev, which is currently identical to master. If dev is defunct this should be retargeted.

[WildBunnie]

we merged #7 so I will close this for now

[jorgeMFS]

Reopening — PR #7 (which led to closing this) only addresses the filename of an upstream LICENSE file (LICENSE.txt, COPYING, etc.). It does NOT cover repos where there is no
separate license file at all — wgsim (lh3/wgsim) is the immediate motivating case: its MIT license lives only in the header comment of wgsim.c. This PR is genuinely complementary to #7, not a duplicate.
Once merged, wgsim recipe (add-wgsim-recipe branch, already pushed) can be PR'd.