Support Julia 1.12 and 1.13, drop Julia 1.11

[ufechner7]

Drops Julia 1.11 and adds Julia 1.13, as KiteModels did in v0.11.19. KiteUtils 0.13 and the WinchModels and AtmosphericModels releases that accept it require Julia 1.12, so #56 can only move forward on 1.12 and 1.13.

Changes

• Project.toml, examples/Project.toml: julia = "1.12, 1.13", Pkg = "1.12, 1.13"
• Manifest-v1.11.toml.default removed; Manifest-v1.13.toml.default added. It was resolved from the 1.12 default, so it has the same package versions; only the stdlibs and the JLLs that ship with Julia differ.
• bin/install: the menu offers Julia 1.12 and 1.13 (default 1.13 if that is the active juliaup channel, else 1.12); only 1.12 and 1.13 are accepted; the juliaup install hint uses channel 1.12
• bin/release: checks Manifest-v1.12.toml and Manifest-v1.13.toml against their .defaults
• .gitignore: Manifest-v1.13.toml and examples/Manifest-v1.13.toml
• README.md, docs/src/index.md, CLAUDE.md: Julia 1.12 or 1.13
• CHANGELOG.md: new Unreleased section

Verification

• bash -n on bin/install and bin/release
• Pkg.instantiate() and precompiling KiteViewers from Manifest-v1.13.toml.default on Julia 1.13.1
• bin/install run interactively
• GitHub CI (runs Julia '1' = 1.13)

Interaction with #56

#56 makes the same julia/Pkg compat, README and docs edits and also deletes Manifest-v1.11.toml.default, so those merge cleanly. Two places will conflict when #56 is updated from main, both easy to resolve:

• bin/release: Make the KA-frame change load against the KiteUtils 0.13 that shipped #56 checks only the 1.12 manifest; take this PR's version (1.12 and 1.13).
• CHANGELOG.md: both add an Unreleased section; combine them.

#56 will then also need its own Manifest-v1.13.toml.default for KiteModels 0.12 and KiteUtils 0.13.

🤖 Generated with Claude Code

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Codecov Report

✅ All modified and coverable lines are covered by tests.

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