cdktf migration: upgrade go and some deps

[filiphaftek]

Summary

• Bump github.com/sourcegraph/cdktf-provider-gen to the current main HEAD (1dd7bde10a62) — the previously pinned commit (ce2a4875e27f) no longer exists upstream (force-pushed/rebased away), which broke go get -u
• Update transitive dependencies pulled in by the new commit's dependency graph (golang.org/x/*, hashicorp/hc-install, ProtonMail/go-crypto, etc.) and bump the go directive 1.25.0 → 1.26.2
• Drop transitive deps no longer required by the updated generator (chroma, glamour, jackc/pgconn, sourcegraph/sourcegraph/lib, etc.)

Test plan

• go build -o .bin/cdktf-provider-gen github.com/sourcegraph/cdktf-provider-gen/cmd/cdktf-provider-gen builds successfully

Tests

Tested e2e via:

1. make install and make -j4
2. used in controller via replace in go.mod
3. regenerated mi2 generate kustomize and all was applied: https://app.terraform.io/app/sourcegraph/workspaces?search=src-95e0e0f227324da05333&sort=-latest-change-at

[michaellzc]

ahh, this was pointing to a commit that no longer exist https://github.com/sourcegraph/cdktf-provider-gen/pull/10/commits because we merged to the PR.

thank you