docs: fix typos and stale references across docs and comments

[redstartechno]

What problem does this solve?

This PR combines five small, previously-separate documentation PRs (#1297, #1299, #1300, #1301, #1302) into a single PR, as requested by the maintainer. Together they fix:

• Markdown formatting glitches in README.md.
• Stale references in README.md: an outdated Go version, a dead launch-script reference, and a renamed directory in the repository-layout tree.
• A srcipts -> scripts typo in inference-chain/readme.md.
• A Duing -> During typo in dev_notes/build.md.
• 16 typos (found with codespell) in comments, docs, and log/error strings across decentralized-api, inference-chain, and testermint.

How do you know this is a real problem?

Each change was verified against the current repository contents:

• Go version (README.md:42): prerequisites said Go 1.22.8, but both inference-chain/go.mod and decentralized-api/go.mod declare go 1.24.2 — 1.22.8 cannot build the modules.
• Launch script (README.md:66): launch-local-test-chain-w-reset.sh does not exist anywhere in the tree (git grep). The real script is local-test-net/launch.sh, whose header describes "1 genesis (seed) + 2 full nodes" (the README's "3 participants") and which does rm -rf prod-local (the "-w-reset" behavior).
• Layout (README.md:100): /prepare-local does not exist; the real directory is local-test-net, which matches the description on that line.
• srcipts (inference-chain/readme.md:19): inference-chain/scripts/init-local.sh exists; srcipts/ does not.
• Typos: the remaining items are misspellings in comments, Markdown, and log/error strings, surfaced by codespell and each confirmed by reading the surrounding context (identifiers and domain terms that codespell flagged were left untouched).

How does this solve the problem?

Each stale reference is updated to the correct, currently-existing target, and each typo is corrected in place. No code logic is changed — only documentation, comments, and human-readable log/error message strings.

What risks does this introduce? How can we mitigate them?

Minimal. The changes are limited to documentation, source-code comments, and log/error string literals; no control flow, types, or APIs change. The log/error string edits are pure spelling corrections within existing messages. Generated files (*.pb.go, *.pulsar.go) and governance/genesis artifacts were intentionally not touched.

How do you know this PR fixes the problem?

Documentation/comment/log-string change only, with no runtime behavior change. Rendered Markdown was visually checked (link and code-span syntax intact). Re-running codespell after the edits reports none of the corrected items remaining.

Which components are affected?

• README.md, dev_notes/build.md
• decentralized-api (one comment, one Markdown doc)
• inference-chain (readme + comments and log/error strings)
• testermint (README, MCP guide docs, Kotlin log/error strings)

Testing & evidence

No code paths changed; unit/integration tests are not applicable. Evidence is the repository checks above (git grep / ls / go.mod) proving each old reference was wrong and each new reference exists, plus a clean codespell re-run. Diffstat: 19 files, 23 insertions(+), 23 deletions(-) — every file a one- to five-line spelling/reference correction.

Supersedes #1297, #1299, #1300, #1301, #1302.